[Music]
the year 2020 will no doubt be a big
year for science it's a new decade and
at times like these we often take the
opportunity to look back and see how far
we've come
scientists who came before us made sure
our food and drugs are free from poison
and built the devices that make our
modern lives possible so as we forge
ahead into the new year let's take some
time to thank the intrepid researchers
volunteers and even the occasional dog
who got us to this point
first up imagine volunteering to be
poisoned in the name of making food
safer for everyone that really happened
in the early 20th century these
experiments weren't terribly safe or
ethical or rigorous but they are the
reason you can be confident your food
doesn't have washing powder in it let's
go to Stefan for more
I think we can all agree that food is
pretty great so participating in an
experiment where almost all you have to
do is eat three delicious meals every
day for up to a year sounds kind of like
the dream but imagine knowing that
hidden in one of the foods maybe the
butter maybe the freshly picked peas is
a substance that's probably toxic sounds
unthinkable today but that was the set
up of some of the strangest and most
infamous human experiments in American
history known as the poison squads they
ran for five years starting in 1902 and
even though they wouldn't pass any
scientific ethics committee today
they were revolutionary at the time
because people started to realize that
maybe they should make sure the things
are safe to eat before eating them the
trials were the brainchild of Harvey
Washington Wiley the head chemist with
the US Department of Agriculture back
then food additives didn't have to be
tested or even put on labels and he
wasn't really okay with the idea that no
one in America had any way of knowing
what they were actually eating unless
they had grown or raised at themselves
formaldehyde for example regularly
popped up in milk to keep it from sour
yeah the known carcinogen that we used
to preserve dead bodies he'd also often
find borax a mineral that contains
sodium and boron in meat made the meat
firmer which made it seem fresher
especially when combined with an extra
pinch of salt and red food color these
days borax is a common ingredient in
things like detergent and pesticides and
we're not talking tiny insignificant
amounts of this stuff either no one had
bothered to investigate whether these
additives were actually safe to eat
so with 5,000 bucks from the government
Wylie hired a chef promised a bunch of
otherwise great free food and recruited
a dozen healthy young men as volunteers
he took their weight in vitals made them
collect their urine and feces and gave
them weekly physicals then they started
with a low dose of a specific chemical
and went up stopping only when the men
were too sick to continue the first
poison Squad tackled borax and it's
derivative boric acid because they were
so common at first the chef hid the
chemicals in butter or milk but the
volunteers could taste the metallic
flavor and instinctively avoided it
because no one wants to eat butter that
tastes like their silverware Riley still
needed the men to get the right dosage
so he just put the borax and pills for
them to pop about halfway through their
meals Bon Appetit the guys on the poison
squad reported stomach pains and feeling
less hungry when
were fed two to three grams of borax a
day had four grams they became very
tired developed headaches and couldn't
work normally which sounds like an
average Monday to me but apparently in
their case it was caused by the borax
through other trials Wiley also found
that if they took a lower dose of half a
gram a day for long enough they'd get
similar symptoms today we know that
eating borax can cause tissue damage
which can eventually lead to fund things
like vomiting and convulsions so thanks
for saving us from that one poison Squad
thankfully though almost no one walked
away from these experiments with any
obvious long-term problems Riley also
tested copper sulfate which was added to
things like canned peas to make them
bright green as well as formaldehyde
sodium benzoate and salicylic acid and
while the effects on the men varied
Wiley concluded that none of the
additives were safe today any scientists
looking back at these trials would be
horrified by not only the ethical
problems because giving people
potentially deadly substances even if
they know about them is never okay but
also the poor experimental design for
one thing the participants knew they
were eating a potential poison which
could have easily skewed the symptoms
they reported and made them feel more
sick than they actually were not to
mention that for the most part the
experiment had no real control group in
between testing each substance the
squads were given a break for several
weeks but they weren't asked to continue
reporting symptoms or to keep collecting
their urine or fecal samples you also
can't really conclude much from a small
and specific group of people
Wylie thought that if healthy young men
got sick the same chemical would also be
unsafe for women and children it's not
really how biology works though and a
few dozen white guys didn't exactly
represent all of America but even though
there were a lot of flaws with this
experiment it was the first time
somebody thought to test food additives
and study them one at a time later
research that was actually reliable led
to almost all of these additives being
banned from food except for sodium
benzoate which is a common preservative
in acidic foods like orange juice and
soda but we only use it because we've
tested it and it's considered safe
journalists loved covering the
happenings in the DC lab kitchen so
people across the country started
thinking seriously about the things that
might be used to preserve their food in
1906 partly because of the public's new
awareness Congress passed the Pure Food
and Drug Act a precursor to today's more
rigorous regulations those concerns also
led to the creation of the FDA which is
the organization that
make sure the ingredients in your food
aren't gonna kill you for the most part
anyway if you decide to crack open ten
thousand cans of baked beans there's not
much they can do to help that one's on
you since Wylie was so instrumental in
protecting America's food he's often
called the father of the agency so the
poison squads were a really horrible
idea and full of sketchy science but
because of the progress we've made since
then going to the supermarket today is a
whole lot safer
I don't know I hear formaldehyde laced
beans are pretty tasty a lot of our
historical episodes have looked at
medicine and health
maybe that's because saving a lot of
lives is a pretty good way to be
remembered but it's not just drugs that
have changed our lives for the better
like all the work that went into
bringing you the phone that's probably
in your pocket right now or at least
somewhere within arm's reach for phones
the ubiquitous pocket electronic device
was the calculator less glamorous sure
but there's a lot going on with that
little four function piece of plastic
your teachers passed around in
elementary school here's Hank with more
we don't think of pocket calculators as
being all that special these days
they're cheap easy to use and your phone
can do all that stuff anyway right but
the development of the pocket calculator
mirrors the electronics revolution that
brought us smartphones and modern
computers in fact some technologies we
now take for granted found their first
widespread use in electronic calculators
in the 1960s and 70s and the first sort
of compact electronic calculators
couldn't fit in your pocket they were
the size of a typewriter and demanded so
much power that they needed a wall
outlet for example the Anita mark 8 was
available in the early 1960s and cost as
much as a car at the time it performed
basic arithmetic functions by using
vacuum tubes basically airtight chambers
with filaments inside which could
shuttle electrons in precise ways to
generate currents and act as switches
the name was short for either a new
inspiration to arithmetic or a new
inspiration to accounting which gives
you a clue as to who bought these
expensive machines but soon there were a
couple major technological leaps that
revolutionized calculators and also the
rest of electronics and the whole world
first for calculators to become cheaper
more portable and less fragile vacuum
tubes were replaced with transistors and
integrated circuits a transistor
functions like a gate for electrons
basically by applying electrical power
it can either be opened or closed these
binary states are still the basic idea
behind all electronics and typically
transistors are made from a material
called a semiconductor which sometimes
conducts electricity and sometimes
doesn't early transistor electronics
like the super popular transistor radio
for consumers would string individual
transistors together in series
transistors were way smaller and
sturdier than vacuum tubes but more
complex devices like computers were
still fairly big in the late 1950s
though engineers invented the integrated
circuit a single semiconductor chip that
had all parts of a circuit on it
including many transistors one of those
engineers worked at Texas Instruments
the company knew it had something good
on its hands but struggled to find a
good consumer outlet for these compact
chips that is until 1965 with the design
of the first prototype electronic
pocket calculator it was codenamed
Caltech measured about 10 by 15
centimeters and could perform the four
basic arithmetic functions addition
subtraction multiplication and division
it's chip required the equivalent of
thousands of transistors they even built
a version for testing without integrated
circuits which according to one designer
took up an entire two-tiered 2 meter
tall desk so integrated circuits really
packed a punch these days we call the
microchips and we put them in the
everything Caltech also printed out
results on a roll of tape using a
thermal printer this was also pretty new
at the time and worked by basically
melting text into a special type of
paper like the receipts you get at the
grocery store see I team actually wanted
an electronic display but that
technology wasn't great yet LEDs at the
time had poor visibility LEDs work based
on passing an electric current or field
through a semiconductor which causes
electrons to shift around and emit light
the color of the light can be altered by
introducing different elements which is
easier said than done it's taken decades
to make LEDs in every color of the
rainbow
early on gallium and arsenic based LEDs
were only capable of emitting infrared
light and very dim red light because of
the way electrons move through those
particular elements lots of pocket
calculators after the Caltech did
feature red LED displays but they
demanded a ton of battery power because
those early systems weren't very
energy-efficient the next revolution in
calculators was the liquid crystal
display or LCD liquid crystals have
molecules that are free to move like a
liquid but can settle into an ordered
state like a crystalline solid dual
identity means they can block or
transmit light and switch between states
rapidly when there's an input like
electricity that's why we use them in
electronic displays the first LCDs were
fragile and only worked at high
temperatures but a breakthrough came in
perfecting a mix of chemicals that
behave as liquid crystals at room
temperature other developments made them
quicker and more durable as well
LCDs used less power than LEDs so
calculators could run off a watch
battery instead of large battery packs
alongside digital watches pocket
calculators were the first widespread
consumer use of the
LCD display nowadays you'll hear about
LED and LCD technologies when you're
researching what kind of TV you might
want to buy over the next few decades
calculators became slimmer cheaper and
more powerful they evolved from
specialized tools for business to a
status symbol to a basic tool that
you're probably gonna get for free as a
promo at an event at certainly where I
got mine but all this development
eventually slowed to a crawl so you
wouldn't carry a separate calculator
either unless you're still in school and
eat it for the SAT or something they've
stayed basic machines to help with
learning not flashy internet-enabled
devices and that is how the Golden Age
fizzled but calculators played a huge
part in the consumer electronics
revolution popularizing display
technology and the computer chip itself
nothing to sneeze at
funny you should mention sneezing yes
were headed back to the world of
medicine specifically the flu there's a
bacterium out there in the world called
Haemophilus influenzae which has nothing
to do with influenza but for a while
scientists thought it did so they gave
it that name how could they make such a
huge mistake stefan explains
if you're coughing sneezing or starting
to feel under the weather you might
blame a virus or possibly a bacteria
which is not something humans have known
to do for very long around 400 BCE
doctors might have blamed an imbalance
of the for vital humors for your illness
and around the 1700s they might have
pointed to an invisible disease carrying
fog instead but today we know pathogens
viruses bacteria and certain other
microbes are responsible for many
diseases but linking specific diseases
to the microbes that caused them has
been surprisingly tricky in 1882 a
scientist named Robert Koch demonstrated
that the bacterium Mycobacterium
tuberculosis causes tuberculosis and in
1890 he also published a framework for
future scientists to make similar
discoveries created a checklist for
researchers to reference anytime they're
trying to link a pathogen to a disease
the steps are as follows first
researchers had to be able to find the
pathogen in sick organisms but not in
healthy one second it could be grown in
pure culture which means that a sample
of the microbe could be taken from a
sick organism and then the microbe could
grow independently in a 19th century
version of a petri dish third if they
exposed a healthy organism to the stuff
that they grew in step two that organism
would get sick with the same disease and
finally although this step is sometimes
considered optional the same microbe
that was isolated in step one must be
found again in the organism made sick in
step three
these steps are now known as Koch's
postulates the idea is that if the
microbe meets all of the postulates then
you know it's the cause of the disease
unfortunately his postulates had a few
problems take postulate one tuberculosis
can actually be found in healthy
individuals
that's called latent tuberculosis so it
doesn't meet cokes first postulate this
situation just didn't show up in his
experiments which were done in guinea
pigs postulate three isn't perfect
either assuming that any healthy
organism exposed to a pathogen will get
sick ignores differences in immune
systems a healthy organism might be able
to fight off the infection or might
already be immune to the disease but it
was the second postulate that caused the
most confusion something grown in pure
culture has to be the only living thing
in the dish and many pathogens just
can't grow independently like that
viruses for example reproduced by
hijacking molecular machinery in the
cells of the organism they're infecting
meaning you can't grow them in a dish by
themselves but bacteria
often grown a dish just fine because
postulate 2 required the thing to grow
in culture researchers at the turn of
the 20th century would almost
exclusively blame bacteria for the
diseases they were studying which
resulted in some false accusations
malaria which is actually caused by
blood infecting parasites was blamed on
a bacterium from Italian marshes in the
1880s which they named bacillus malaria
canine distemper sometimes deadly
disease in dogs that causes symptoms
like fever and vomiting was linked to a
series of different bacteria before it
was finally proven to be a virus in the
1920s and the familiar influenza or the
flu was misidentified as a bacterium in
1892 by a colleague of coax the
bacterium came to be known as
Haemophilus influenzae to study the flu
researchers needed samples of spit and
snot from people with obvious symptoms
but one thing that made influenza hard
to study was that even though the flu
usually reaches a peak in winter the
only time that scientists could reliably
find large numbers of flu ridden folks
at the same time was during a pandemic
and those could be decades apart so the
first chance scientists had to check the
results from 1892 was during the next
influenza pandemic in 1918 and the
researchers were unable to replicate
those initial results but it wasn't
clear at the time if it was because of
poorly controlled studies in the chaos
of one of the worst pandemics in recent
history and the end of World War one or
if they were just wrong a vaccine was
developed in New York based on hema
Phyllis just in case there was at least
one study around that time that managed
to find evidence of the right answer
influenza is a virus but it took until
1933 and another influenza pandemic for
scientists to prove without a doubt that
the flu is caused by a virus thanks to
the introduction of ferrets as a model
organism ferrets were the only small
mammals they could find that could
actually get the flu and show symptoms
similar to ours so it seemed like Koch's
postulates especially the second really
hindered research into any disease that
didn't have a bacterium behind it but
does that mean they're useless
not at all since the 1880s scientists
have tweaked Koch's postulates over time
to match modern understandings of
pathogens today the focus isn't just on
microbes but on their genes using
genetic sequencing scientists can gather
information about all of the nucleic
acids in a sample whether DNA or RNA and
then use a modified version of Koch's
postulates to figure out which genes are
most
associated with disease symptoms for
example in 1996 scientists at Stanford
came up with a new set of postulates
with seven gene-centric points by using
gene sequencing scientists can find
pathogens that haven't been isolated and
identified before and there's no need to
culture that Koch's postulates provided
a solid foundation for researchers to
begin linking diseases to their sources
and sure there were a few mistakes but
they provided a rigorous testable basis
for understanding disease even if we had
to come along and make some changes
later and even if some ferrets had to
get the sniffles
incremental progress is the name of the
game in science being wrong is often not
a bad thing at least not with the right
attitude but sometimes it's more about
quiet persistence even when your
colleagues think you're wrong some
scientists are never recognized in their
lifetimes despite saving tons of lives
and practically defining their field
like Jon Snow
not that Jon Snow here's Hank to tell us
more
these days most people are like me they
hear the name John snow and they think
of Game of Thrones or they think of that
British news anchor but before there was
John snow the news anchor and before
there was John snow the fan beloved
brother of the Nights Watch
there was Jon Snow with an H the 19th
century medical doctor from England but
dr. Jon Snow has a few claims to fame
including developing early anesthetics
and administering anesthesia for the
Queen while she delivered two of her
kids but mostly he is remembered for the
way he fought cholera in the 1850s his
timely action and clever thinking
stopped an outbreak and even though he
was never recognized during his lifetime
he's now considered one of the founders
of Epidemiology our story begins in mid
nineteenth century London which was in a
word gross in two words similar gross
like many cities in the eighteen
hundred's London saw a huge increase in
population and with that came a huge
increase in poop which nobody knew quite
how to deal with sewer systems hadn't
quite spread to the entire city so in
places like the Soho district people
sloshed their waste into the streets
dumped it into overflowing cesspools or
trucked it over to the Thames river the
river that notably also served as the
city's primary water supply during this
period maybe unsurprisingly London and
the rest of Europe were also being
plagued with persistent outbreaks of
Cholera a highly infectious sometimes
deadly diarrhea illness and there was
considerable disagreement over why we
didn't know that bacteria and viruses
were at the root of most infectious
diseases so the prevailing idea was
miasma theory which said that they were
passed around by bad air this is where
Jon Snow came in he had encountered
cholera before in mining populations and
had come to believe the disease was not
spread by air but by ingesting stuff
contaminated with human waste after all
the miners brought their meals to work
didn't have a bathroom down there and
probably didn't wash their hands before
eating gross when snow observed the
situation in London he therefore
concluded that cholera was being spread
by tiny fecal particles in the water and
in 1854 he got a
to prove it the year before a new collar
outbreak reached a London borough near
snows home and it killed more than 500
people in a matter of weeks based on the
area snow was suspicious of one water
pump on Broad Street specifically after
his sample of the water turned up
visible white flecks of organic material
so he obtained a list of some people who
had been killed by the outbreak and
began talking to their families and
ultimately he found the common factor
was where those victims had gotten their
water that pump on Broad Street snow
then took his evidence to the local
officials who agreed to take the handle
off the pump to prevent people from
using it but even then nobody really
believed snow about why including
Britain's general Board of Health it's
possible that his sample size wasn't
enough to convince them or maybe it was
the fact that he couldn't prove what in
the water was causing the illness in any
case
snow was confident enough in his
findings that when other cholera
outbreaks appeared he continued trying
to find the contaminated water behind
them and ultimately that led him to a
more citywide discovery at some point
snow realized all the districts in
London affected by the outbreaks had
their water piped in from one of two
suppliers one that got their water from
upstream of London and one that got it
from downstream he suspected the
downstream water as you might also
suspect had a bunch of sewage in it so
cholera should have been more common in
the neighbourhoods that drink it to
prove this he began rifling through
hundreds of parliamentary death Records
and he found that areas with downstream
water had 14 times more deaths from
cholera during the outbreak now to you
and to me that might seem like pretty
conclusive evidence that sewage equals
cholera but for various reasons the idea
still didn't catch on and that was the
end of that or at least it was snows
last published attempt at convincing the
medical community that sewage caused
cholera he did continue to investigate
it privately and do other kinds of
research but unfortunately he died
prematurely only a few years after these
events the thing is though snow was very
right
is typically a waterborne illness spread
by sewage contaminated water it just
took a few more decades of work and
proof that microbes can cause diseases
for scientists to finally prove and
accept that thankfully for all of us
though snow's methods didn't fade into
obscurity
even if his work was rejected in the
1850s his outbreak management strategies
are still in use today his idea to map
the origin of cases is a technique that
is currently saving lives and it was so
unique that it was a foundation of
modern epidemiology looking back dr.
John snow may not have had a sword he
may not have had an army at his command
but he did wield mass health information
and helped shape a major field of
science so even though snow wasn't
celebrated during his lifetime there's a
lot to celebrate about him today because
in the end there's no doubting that his
contributions have helped save millions
of lives
next let's look at two serious tragedies
that ultimately made our drugs safer
there was a time in the United States
that you had to label what was in your
medication but no one regulated what
counted as medication meaning you could
sell poison to people as long as you
were upfront about it weirdly enough and
as you might predict that resulted in a
few deaths but also stronger rules
here's Stefan to explain what happened
the history of medicine is full of some
huge triumphs but also some pretty
terrible mistakes like in the 1930s a
company out to make a quick buck took a
safe effective drug and managed to make
it a killer
surrounding that tragedy are some pretty
fascinating stories Howard I became a
wonder drug how the US FDA became what
it is today and how one scientist walked
home with a Nobel Prize the drug in
question is called elixir sulfanilamide
and it was briefly manufactured and sold
by the SE massingill Company of
Tennessee in 1937 but before this deadly
elixir was concocted sulfanilamide had a
good rep as an effective drug all on its
own sulfanilamide is an antibiotic so
it's used to fight bacterial infections
it works by interfering with bacteria's
ability to make folic acid which they
need to reproduce it was derived from an
earlier drug called pronto cell which
had a vivid red color and was actually
developed by the dye industry in 1932
chemist gerhard omok found that this
molecule wasn't just pretty it could
cure bacterial infections in mice and
once pronto still hit the market in 1935
it quickly gained popularity and saved a
lot of lives in fact pronto sill and
related compounds were some of the
earliest widespread antibiotics
penicillin had already been discovered
but it wasn't easily available yet
further research showed that there were
two parts to the Pronto cell molecule
one part was the dye and the other was
the antibiotic the antibiotic half was
sulfanilamide which researchers found
could be used on its own mostly in
powder or pill form well it had
potential side effects it was generally
safe we actually still use sulfanilamide
to treat vaginal infections though not
very often because there are other anti
microbials out there nowadays the
problem was that sulfanilamide had
already been synthesized by chemists and
the patent had expired so anybody could
make in cell variants of it enter the
massingill company who found that their
customers liked their drugs in syrup
form they set out to make a liquid
version of sulfanilamide and their
researchers eventually found that the
powder would dissolve in diethylene
glycol at the time diethylene glycol was
known as a solvent it had a sweet taste
and smell and once the lab added some
caramel and raspberry flavoring they
figured they had a nice medicine and
released it as an antibiotic elixir
frankly it sounds tastier than some of
the cough syrups I've had for one thing
diethylene glycol is super poisonous
back then there were one or two
scientific studies about it stucks
city but they weren't widely known these
days it's used as antifreeze among other
things and we know it's not a sweet
treat inside your body diethylene glycol
takes time to do its dirty work at first
the symptoms resemble drunkenness but
after several hours the poisoning gets
worse while scientists aren't exactly
sure how it kills we do know it gets
broken down by your liver into a nastier
form from there it shuts down the
kidneys and can affect the nervous
system to the instructions that shipped
with the deadly elixir sulfanilamide
said to keep giving it to patients until
they got better which means that some
people were poisoned by well-meaning
loved ones who fed them antifreeze for
days or weeks until they succumbed
usually from kidney failure in total at
least a hundred and five people died and
if massingill had just fed it to a
handful of mice before shipping a bunch
of it out this tragedy might have been
prevented before 1938 the US FDA only
had the power to prevent adulteration
and mislabel who couldn't for example
sell tablets of flour and say it was
medicine that was against the law but
you could sell something that was
poisoned with zero safety testing before
hand as long as it was what you said on
the label massingill company's elixir
contained exactly what they said it did
sulfanilamide and diethylene glycol with
some water and flavoring but they did
technically break the law they called
the stuff in elixir but that word was
only supposed to be used for products
that contained ethyl alcohol and
massingill syrup had none the FDA seized
on this technicality they used it to
track down the tainted medicine and
slapped massingill with an unprecedented
fine if not for the fine print they
would have been helpless and many more
people could have died but a new law was
rushed through Congress in 1938 giving
the FDA increased power over drug safety
that law is credited with preventing the
infamous drug thalidomide which was
found to cause severe birth defects from
hitting the US shelves many years later
in the aftermath of this tragedy and new
legislation the chemist responsible for
the antifreeze elixir committed suicide
and the senator who sponsored the 1938
drug law died shortly after it passed
reportedly of exhaustion powder in pill
forms of sulfanilamide were still being
made in labs and widely used as
antibiotics by American soldiers in
World War two
as for gerhard omec developer of pronto
sill he won the 1939 Nobel Prize in
Physiology or medicine for helping to
usher in the antibiotic era because
really pronto sill sulfanilamide and
related compounds were used a lot at the
time
can be safe and effective antibiotics
you know as long as you don't take them
with antifreeze
stephane mentioned thalidomide and he's
got that story too here's how incredibly
subtle differences in chemistry can
sometimes mean life or death
first 1957 a new over-the-counter drug
was introduced in West Germany that was
supposed to basically cure morning
sickness during pregnancy it was called
thalidomide thousands of women purchased
the drug and were relieved when their
morning sickness disappeared and
everything seemed great until later the
next year when thousands of infants were
born with severe birth defects like
brain damage and deformed limbs doctors
noticed the surge but at first they
couldn't figure out what was causing
then two doctors vidiq and lens from
Germany and William McBride from
Australia both noticed that the mothers
of these babies had all taken that
amazing new morning sickness drug by
1961 lens had proven the link between
fluid amide and the birth defects and it
was pulled from the shelves but by then
thousands of infant's had been born with
those birth defects and nearly 40% of
them had passed away rules for drug
testing weren't as strict back then and
in this case that cost thousands of
lives even though they were now aware
that filler amide was a problem
scientists still didn't know why turns
out the answer lies in its chemistry or
more specifically its geometry what
researchers didn't know at the time was
that there were actually two versions of
the thalidomide molecule solute amide
which is made up of three connected
rings of carbon and nitrogen atoms plus
some oxygen and hydrogen is what's known
as a chiral molecule chiral comes from
the Greek for hand or claw and chemists
often think of chiral molecules as being
right-handed or left-handed that's
because the different versions of chiral
molecules called enantiomers are made up
of all the same parts but arranged
differently
just like your hands if you try
overlaying your right hand on your left
you'll see that no matter which way you
turn your hands you can't make them
match up even if you make your thumbs
line up one hand is palm up and the
other is palm down in other words both
hands have the same five fingers but
they're not identical and molecules like
thalidomide are the same way a chiral
molecule has an atom typically carbon
with four different groups attached to
it that's called the chiral Center a
group can be anything from a single atom
to a long-chain two rings in some cases
two groups can even be connected these
groups are kind of like your fingers in
each and antium ER the groups are
attached the chiral Center in the
opposite order so they're mirror images
of each other in thalidomide for example
the chiral Center is a carbon atom
attached to one of the rings it's bonded
to two other carbons a nitrogen and a
hydrogen
if you position the version
the molecule that's considered
right-handed called the R enantiomer so
the closest oxygen atom to the chiral
Center is below it the hydrogen atom
attached to the center will be facing
away from you but if you position the
left-handed or S enantiomer the same way
the hydrogen atom will be facing toward
you in other words the two enantiomers
are mirror images of each other because
different receptors and enzymes in your
body react with molecules in very
specific ways the fact that enantiomers
are mirror images means that they might
react to things totally differently in
the case of thalidomide scientists
discovered that the R enantiomer helped
with morning sickness but the S
enantiomer caused those severe birth
defects one of the most famous or maybe
infamous examples of how two enantiomers
affect the human body is methamphetamine
you'd probably associate that name with
the street drug but the molecule can
only really break bad when it's in its
are formation the S enantiomer is
commonly sold over-the-counter as a
vasodilator and you can easily find it
in vapor inhalers but the vapor inhaler
you just bought at the pharmacy isn't
filled with a dangerous drug because the
S version will never be psychoactive
after researchers discovered that only
the S version of thalidomide cause birth
defects they thought about isolating the
R enantiomer so they could continue to
use it to treat morning sickness but it
turns out that the lid amides are
enantiomer can actually switch to the S
version while inside the human body
meaning that even if they dice elated a
hundred percent pure our thalidomide it
still wouldn't be safe for pregnant
women but in 1998 the FDA did approve
the lid amide almost 40 years after
rejecting it based on the birth defect
problems this time though it was
approved for treating complications from
Hansen's disease
aka leprosy and recent research is also
leading some scientists to believe that
in certain cases the lid amide could
help with a number of debilitating
diseases including some forms of breast
cancer they just make sure not to
prescribe it to anyone who's pregnant
I hope you're all enjoying this showcase
of Stefan's shirts by the way does he
called dibs and all the history episodes
oh wait here's one from me it's about a
deadly disease a desperate race and one
very very good boy
even if you're not big on Alaskan
history you might have heard of the
Iditarod sled dog race every year since
1973 people have raced their dog teams
across the 1500 kilometer stretch of
Arctic tundra between Anchorage and Nome
Alaska the race starts on the first
Saturday in March and to win
participants have to charge through some
of the harshest conditions in the
northern hemisphere but it's not an
exercise in torture it's inspired by
what sometimes called the great race of
Mercy where dogsled teams raced along
much of the same trail to deliver an
antitoxin that would save thousands of
people from a deadly diphtheria outbreak
in the winter of 1925 in the early
1900's most of Alaska's remote towns
were pretty much inaccessible during
winter train tracks connected the
largest cities but the most reliable way
to travel between most places was by
dogsled driven by so-called mushers and
pulled by teams of dogs these sleds were
used to transport people Goods and Mail
during the long winters when the severe
weather knocked boats and planes out of
commission in January 1925 that dogsled
transportation network became one town's
last hope in December of 1924 curtis
welch the only doctor in nome alaska was
treating an outbreak of sore throats and
coughs in the towns children which he
initially diagnosed as tonsillitis a
simple viral infection when two of his
patients died he realized he was facing
something much more serious diphtheria
an extremely contagious disease caused
by the bacterium corynebacterium
diphtheria it spreads through tiny
droplets of mucus coughed or sneezed at
by infected patients which linger in the
air and on surfaces at first the disease
looks a lot like tonsillitis or even a
common cold but it's way more deadly
because the bacteria invade the
patient's upper respiratory tract and
produce a type of cell slaying protein
known as an EXO toxin once it makes it
into host cells the exotoxin protein
keeps them from manufacturing their own
proteins which rapidly kills them as
dead and dying cells slough off the
victims nose and throat and mix with the
growing bacterial colonies they form
these thick leathery grey coatings
called pseudo membrane they can make it
hard to swallow or even breathe and
without treatment the disease kills more
than half of its victims even back in
1924 it could be treated scientists
would inject diphtheria into animals
that were less susceptible to the
disease and collect the antibodies they
produced a response and used them to
make an antitoxin serum when it's
treated with the
Thaksin the death toll from diphtheria
drops to one in ten unfortunately for
the residents of Nome
the town's supply of antitoxin had
expired and the vaccine developed in
1921 hadn't been administered widely to
keep the outbreak from getting even
worse Welsh put the entire town under
quarantine to reduce the spread between
families and keep the disease from
reaching the roughly 10,000 people in
the rest of the region but without the
antitoxin thousands of people were at
risk of infection and death a national
search found a suitable supply of the
antitoxin in Anchorage Alaska but no one
was sure how to get it to Nome the
closest trains brought it to Nenana
which is still more than a thousand
kilometers away planes back then were
open cockpit and with the worst weather
in 20 years they weren't an option and
sea ice blocked the shipping route so
the governor of the Alaskan territory
turned to 20 of the best mail carrying
dogsled teams to take the precious serum
on the last leg of the journey over five
days 20 mushers and 150 dogs carried the
9 kilogram package of antitoxin between
relay points fighting whiteout blizzard
conditions and temperatures of negative
45 degrees Celsius across a trail that
normally took three to four weeks to
complete four of the animals died in the
process the teams averaged about 48
kilometers each although some went much
farther than others
Leonhard Seppala and his lead dog togo
traveled a hundred and forty six
kilometers over the tundra and crossed
the icy surface of the frozen Norton
Sound the last team led by musher Gunnar
casein and his lead dog Balto made the
trek to Nome in a whiteout so bad that
Kayson said he couldn't see any of his
dogs he relied on Balto sense of smell
to guide them they reached Nome in the
early morning of February seconds just
five days and seven hours after the
serum was picked up by the first musher
thanks to the rapid delivery of the
antitoxin only five of nomes 1400
residents died during the outbreak the
national publicity of gnomes dire
situation fueled a campaign by health
officials to widely vaccinate against
diphtheria in the United States and that
continues today with the Tdap vaccine in
the 1920s there were a hundred thousand
to two hundred thousand cases and 13,000
to 15,000 deaths from diphtheria every
year but the US has only recorded five
cases in the last decade and the state
of Alaska still runs a yearly
immunization drive alongside the
commemorative Iditarod sled dog race so
in a way those
teams saved an uncountable number of
lives
all dogs are good dogs but like these
guys were the best finally I said before
that historical episodes like these are
why our food and drugs are free from
poison notice I didn't say drinks is
that you want to be technical alcohol is
a poison but there was a time when the
US government made it more poisonous
once more here's Stefan to tell us why
they thought that was a good idea
on Christmas Eve 1926 more than 60
people ended up in a single Hospital in
New York City they were violently ill
and hallucinating and despite doctors
best efforts within a few days about
half of them died but it wasn't a
virulent flu or poorly chosen mushrooms
that caused their deaths it was alcohol
that had been poisoned by the US
government which sounds like a
conspiracy theory but it's the truth in
the twenties a chemical war between
government regulators and illegal booze
cellars resulted in tens of thousands of
poisonings and hundreds maybe even
thousands of deaths in the u.s. the
roaring 20s were a decade filled with
jazz flapper dresses speakeasies and
lavish parties like the ones in The
Great Gatsby even though America was
supposed to be a dry country the 18th
amendment which banned the production
sale import and export of alcoholic
beverages came into effect in 1920 and
it wasn't repealed until 1933 but plenty
of people still drink even though that
sometimes meant risking their lives when
alcohol became illegal people turned to
the black market for their booze and
thanks to heavy enforcement at ports of
entry smugglers could only bring in so
much so the bootleggers that trafficked
in illegal alcohol often stole
industrial alcohol instead ethanol the
main kind of alcohol in alcoholic
beverages is used in everything from
cosmetics to pharmaceutical products to
house paint but at the turn of the
century import taxes made it really
expensive to use pure ethanol that way
because it's technically drinkable so
starting in 1906 almost 15 years before
prohibition the US government began
adding toxic chemicals to industrial
alcohol to make it cheaper a tactic
already used in other places like Europe
industrial formulas were spiked with
well-known toxic compounds like gasoline
chloroform and methanol and because that
made them undrinkable when the 18th
amendment went into effect they weren't
covered by the ban but for the most part
all one had to do to make them drinkable
was distill them that's the process
where alcohol is boiled and then it's
vapor is collected and cooled and when
done carefully it can get rid of small
amounts of toxic additives if their
boiling points are different from
ethanol during the first several years
of prohibition the US Treasury
Department estimated tens of millions of
gallons of industrial alcohol were
stolen for human consumption
so in 1926 President Calvin Coolidge
used the help of chemists to make these
already toxic alcohols even more
dangerous
particularly by adding methanol there
was already some methanol in most
industrial alcohol formulations but the
government added more a lot more to the
point where it was sometimes 10 percent
of the entire product and that change is
probably what caused so many poisonings
and deaths no alcohol is great for you
but methanol is much worse than ethanol
the two chemicals only differ by a
carbon and two hydrogen's but that's
enough to make one drinkable and the
other lethal in your liver an enzyme
called alcohol dehydrogenase removes
hydrogens from alcohols ethanol is
converted to acetaldehyde and then
eventually to acetic acid the same stuff
in vinegar methanol is also processed by
this enzyme but the losses of hydrogens
create formaldehyde and then formic acid
instead and formic acid is bad it
inhibits a key enzyme that your cells
need to convert sugar and oxygen into
usable energy so even though they've got
plenty of food your cells basically end
up starved that's why the buildup of
formic acid in someone's body can cause
a range of horrifying effects from holes
in the stomach and intestines to
vomiting blood and kidney failure one of
the most common symptoms though is
hallucinations like the ones experienced
by all those people rushed to that New
York Hospital in 1926 that's because
your optic nerves the nerves that
transfer visual information from your
eyes to your brain need a lot of energy
to function so they're among the first
to feel formic acid toxic effects and
that damage can be permanent which is
why methanol poisoning frequently causes
blindness now in principle even 10%
methanol can be distilled away but the
bootleggers chemists didn't have the
best equipment and they were pressed to
work quickly and since booze was illegal
no one was checking their product to
make sure it was safe although the exact
figures aren't known by the time
prohibition ended in 1933 some estimate
that over 10,000 people had died from
drinking government poisoned alcohol
killing people wasn't the goal but it
was the result and these deaths became a
hot-button political issue
so as the 20s came to a close regulators
slowly started switching to less toxic
dyes and noxious compounds that couldn't
be distilled away for example in 1930
the US government announced the
discovery of alket a sulfuric compounds
that smells like rotten eggs which isn't
exactly an appetizing scent for a gin
and tonic some industrial formulations
still included methanol and some still
do today but when the 18th amendment was
repealed there was much less incentive
to drink them so nowadays thankfully
methanol
poisonings in the u.s. are relatively
rare
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